British Patent Specification 1,225,956 discloses a process for the production of a chlorofluoroethane of the general formula CH.sub.3-n Cl.sub.n CClF.sub.2 where n is 0 to 3 comprising the photochemical chlorination of 1,1-difluoroethane, which may contain less than 2% HF.
There has been considerable interest in processes for the chlorination of aliphatic hydrofluorocarbons and hydrochlorofluorocarbons which avoid using expensive actinic light to effect such chlorination.
U.S. Pat. No. 4,490,534 discloses a process for the preparation of 3-chloro-5-trifluoromethylpyridine derivatives comprising reacting a 5-trifluoromethylpyridine having a hydrogen atom at the 3-position with chlorine in the presence of a catalyst selected from the group consisting of activated carbon and a chloride of a metal selected from the group consisting of iron, antimony, copper and zinc.
Many processes have been disclosed for the preparation 2-chloro-1,1,1,2-tetrafluoroethane (i.e., HCFC-124 or CF.sub.3 CHClF) and of 1,1,1,2-tetrafluoroethane
(i.e., HFC-134a or CF.sub.3 CH.sub.2 F) which are useful refrigerants, propellants, and starting materials for producing various other halogenated hydrocarbons. 2,2-Dichloro-1,1,1,2-tetrafluoroethane (i.e., CFC-114a or CCl.sub.2 FCF.sub.3) is a chlorofluorocarbon which has been used as an intermediate for the preparation of HCFC-124 and HFC-134a. More particularly, CFC-114a can be converted to HFC-134a as the major product and HCFC-124 as a minor product, by catalytic hydrogenolysis. HCFC-124 has also been prepared by the addition of HF to halogenated olefins and by the reaction of 2,2-dichloro-1,1,1-trifluoroethane with HF. HCFC-124 is also useful as a heat pump working fluid and as a blowing agent. There is interest in developing efficient methods of producing CF.sub.3 CHClF.